<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Document</title>
  </head>
  <body>
    <script>
      var stu3 = {};				    // 创建一个空对象
      console.log(stu3.name);		// 输出结果：undefined
    </script>
  </body>
</html>